The study is a two-year observational prospective study of 1000 male veterans aged 50 and older. The subjects are drawn from two existing VA cohorts, the Normative Aging Study (NAS) and the Veterans Health Study (VHS). Examinations to be performed on each subject (baseline and two follow-up exams) include BMD measurement at the hip, forearm and total body, anthropometry, hand grip strength, and questionnaires on current diet, physical activity, tobacco, alcohol use, sunlight exposure, health related quality of life (Medical Outcomes Study Short Form), depression (Brief Depression Scale), fracture history, medications and psychological factors (PrimeMD, MiniMental). Additional data on historical exposure to risk factors, previously obtained in the NAS or VHS studies, will also be correlated with BMD and BMD loss. Multivariate linear and logistic models with control for potential confounders will be used in the main analyses. Examinations take place at the Boston VA Outpatient Clinic.